1. Field of the Invention
The invention relates to a hydrodynamic converter with a pump wheel, a turbine wheel and/or with guide blades.
2. Description of the Related Art
Hydrodynamic converters have long been known, see for example WO 02/14 706 A2 (=D1), U.S. Pat. No. 3,888,082 (=D2).
Converters of this kind are usually interposed between an engine and a work machine. Their application in motor vehicles is very common.
An important quantity is the torque MT which can be delivered by the turbine of the converter to the work machine. It is influenced by the torque MP of the pump, and also by the speed ratio of the turbine to the pump, v=nT/nP. The speed ratio is at 0.95 to 0.98 when using hydrodynamic converters in motor vehicles (cf. “Kraftfahrtechnisches Taschenbuch” (Pocket book on automotive technology), Bosch, 22nd edition (=D3), page 558, left column).
The most important advantages of a hydrodynamic converter are the infinite variability in the change of speed and torque, in the oscillation dampening and the reduction of torque peaks. In practice, they are only operated in conjunction with mechanical multi-step transmissions (cf. D3). It is stated there on page 557, right column, that hydrodynamic converters can only be operated economically in conjunction with mechanical multi-step transmissions because permanent operation with high slip is only possible within limits with respect to efficiency.
There are a large number of different designs of converters. Pump and turbine can thus rotate in the same direction. The pump wheel and the turbine wheel (when seen in an axial sectional view) can be arranged on one and the same side of the flow circulation. They can also be situated opposite of each other.
Furthermore, pump wheel and turbine wheel can rotate in different directions, with a reversing guide wheel between pump wheel and turbine wheel.
Guide wheels can be adjustable or non-adjustable and can be configured in different ways.
The known converter designs have not been satisfactory in all cases. This applies especially concerning the need for space, and the overall costs for the drive train.